DESCRIPTION: The main objective of the proposed work is to develop field-flow fractionation (FFF) and its various sub-techniques into increasingly powerful tools for the separation and analysis of complex colloidal and macromolecular materials of biological and pharmaceutical origin. Theoretical and experimental studies will be combined to exploit the unique capabilities of FFF to fractionate and characterize high molecular weight materials relevant to the health sciences. The proposed work will be divided into several categories. In the first category, the investigator will pursue the optimization of FFF to yield higher speed, resolution, and convenience. He will convert optimization theory to simple laboratory guidelines. He will also study fundamental colloidal phenomena related to FFF and continue to develop new techniques and modifications of FFF. In the second category, the investigator will intensively develop flow FFF, the most widely applicable of FFF techniques. He will characterize and develop ultrathin channels for high- speed flow FFF analysis and undertake other studies to improve and automate this technique. In the third category, the investigator will utilize his on- line sample concentration technique to implement the coupling of sedimentation FFF to flow FFF for the characterization of complex colloidal fluids such as cell lysates. In the fourth category, he will develop applications and new application strategies. These will complement his basic studies. Applications work will be directed at biological cells, motile bacteria, protein complexes, protein inclusion bodies, colloids in blood plasma, liposomes, and other classes of biological and biomedical materials.